Printer hammer mechanism

ABSTRACT

A printer has a type cartridge with a plurality of characterbearing type levers, alternate levers having faces on the back at different levels. Print hammers for each print position have striking faces covering both levels, and selection of the type levers is made by operating an interposer between the printer hammers and type levers to the desired level.

O v United States Patent 11 1 1 1 Raider Feb. 13, 1973 [54] PRINTERHAMMER MECHANISM R26,240 7/1967 Wasserman ..101 93 c 75 I 3,575,1074/1971 McDonell ..l0l/93 C Jemfw s Endlcott N Y 3,332,343 7/1967 Sims..101/93 c Assignee; International B sine M hi 2,936,704 5/1960 Hense..101/93 C Armonk 3,331,316 7/1967 Bretti ..197 90 x [22] Filed: Sept.3, 1970 Primary ExaminerWi1liam B. Penn [21 1 A l N 69 317Attorney-l-Ianifin and Jancin and Francis V. Giolma i [57] ABSTRACT i. iA printer has a type cartridge with a plurality of [58] Fieid 1 g 90character-bearing type levers, alternate levers having faces on the backat different levels. Print hammers for each print position have strikingfaces covering 56 R i C t d 1 e erences I e both levels, and selectionof the type levers is made by UNITED STATES PATENTS operating aninterposer between the printer hammers 3,241 480 3/1966 Cunningham ..10193 c and type levers to the desired level l kfisgz 2 Claims, 3 DrawingFigures 3,306,191 2/1967 Sharples 3,433,153 Harrington et al ..l0l/93 CPATENTEUFEB 1 3 1973 JERRY w. RAIDER v T/w M ATTORNEY 1 PRINTER HAMMERMECHANISM DESCRIPTION OF PRIOR ART 7 Heretofore, with moving typecarriers having levermounted type characters, print hammers have beenused, which engage the type letters at a single level, which has beenactuated levers impact a particular type lever, and an adjacent typelever as it moves past the actuated print hammer.

BRIEF SUMMARY OF THE INVENTION Generally stated, it is an object of thisinvention to provide an improved printer mechanism.

Another object of the invention is to provide a printer mechanism inwhich the probability of interference between an operated print hammerand an adjacent type lever is minimized.

More specifically, it is an object of this invention to provide forhaving character-bearing type levers in a printer which have differentlylocated areas of contact with a plurality of print hammers past whichthey are moved.

Yet another object of the invention is to provide for using two groupsof character-bearing type elements having different levels of contactwith a plurality of print hammers past which they are moved, and forutilizing an interposer between the print hammers and the type leversfor selecting which group will be actuated.

Another object of the invention is to provide alternatecharacter-bearing type levers with actuating surface portions atdifferent levels and for utilizing an lnterposer between the type leversand each of a plurality of print hammers, which interposer isselectively moved to one or the other of two operating levels to selectwhich of two adjacent type levers will be actuated by the print hammer.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention as illustrated inthe accom panying drawing.

DESCRIPTION OF THE DRAWING DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1shows a portion of a printer apparatus of one type with which thepresent invention may be used, and comprises a type cartridge 10 havinga plurality of individual type carrier elements represented by the typecarrier element 11, movable in a continuous path on a stationary frame12. A portion of the path of motion of the type carrier elements 1 1includes a straight portion along a guide rail 120 at the print line.The printer apparatus of FIG. 1 is a front printer but is generallysimilar to the back printer, which is described in U. S. Pat. No.3,241,480, which issued on Mar. 22, 1966, to James M. Cunningham and inaccordance with well-known operational principles thereof a paperdocument or form 13 is positioned behind an ink ribbon 14 or the like,which in turn is positioned immediately adjacent the type carrierelements 11 over the print line portion thereof. The ribbon 14 may befed along the print line in any suitable manner while the paper document13 is fed transversely to the direction of motion of the type along theguide rail 12a. Generally, printing occurs while the paper document 13is stationary relative to the print line. On completion of a print cyclethe paper document 13 is advanced one or more spaces to a position wherea new line of data may be printed. The means for feeding the paperdocument 13 properly timed with respect to the operation of the printmechanism are well-known in the art and are not shown herewith.

In the printer apparatus of FIG. 1 the arrangement shown is for a frontprinter. Details of the type carrier element 11 used in the frontprinter, as shown in FIG.

1, include one or more pivotally mounted type levers 11a, for eachcarrier element, each lever with a type character 11b on the free end ofthe lever. The type carrier elements 11 are, as described in theCunningham patent, slidably mounted on the guide rail 12a. As shown,printing occurs when the type characters 11b on the'type levers Ilaimpact against the ribbon 14, paper document 13 and a platen 23positioned behind the document 13. The impacting occurs at various print positions along the print line to eventually form a complete line ofdata. For this purpose, a plurality of print hammers 24 are mounted, asshown in FIGS. 1, 2 and 3, by way of example, on a shaft 25 and arebiased away from the document 13 by means of a spring 26. The printhammers 24 are disposed to be moved to impact the type charactersagainst the document by means of electromagnets (not shown) through themedium of push rods represented by the push rod 30. Each print hammer 24is individually operable, and operation of the various print hammers 24occurs selectively at random positions along the print line inaccordance with instructions from suitable control means (not shown),which may comprise a type tracking device and a co-acting storagedevice, which indicates 'the particular data to be printed. Furtherdetails of a suitable control system may be more fully understood byreference to U. S. Pat. No. 2,993,437 of F. M. Demer and E. J. Grenchusfor a High Speed Printer, which issued July 25, 1961.

According to the present invention, the characters on a type chain areas shown, spaced relatively close together. The spacing closelyapproaches the theoretical minimum dictated by the width of the typecharacter 11b. The effective spacing of the type levers is increased bycausing selective operation of the different type levers throughutilizing an interposer 32, associated with each type hammer 24, andwhich may be selectively operated by means of a suitable electromagneticoperation device 35 to either an upper level, as shown in full lines inFIG. 1, or to a lower level as shown by the dotted outline. The adjacentface 24a of the print hammer 24 is wide enough to span both positions ofthe interposer 32. Adjacent type levers 11a, as shown in FIG. 3, areprovided with striking surfaces a and 15! positioned in line with theupper and the lower positions of the interposer 32, respectively.

As shown in FIGS. 2 and 3, the hammer assembly of the present invention,though physically covering two print positions at once, does noteffectively span more than one position at any one time because of theinterposer 32.

The present invention allows a print hammer 24 to spend more than twiceas much time in penetrating the type line without hitting an adjacenttype lever. Also, it increases the contact area between the print hammerand the type lever, thereby decreasing wear. This is accomplished byhaving two kinds of type levers. Half of the type levers have a strikingsurface or face on the back of the type lever, which is twice the widthof the type lever spacing, and this face 15u will be located, forexample, at an upper level. The other half will have a face 151 of equalwidth located at a lower level, as shown in FIGS. 1, 2 and 3. Theinterposer 32 between the type hammer 24 and the type levers'lla will bemoved to an upper level u or to a lower level 1 during the time that thepaper is indexed. If the interposer 32 is at the level u, a typecharacter with a face at level u will be hit by the type hammer 24 andprinted. If the interposer 32 is at a level I, a character with a faceat level l.will be printed.

For example, a 48-character set on a type chain would be divided intotwo equal groups; 24 of the characters would be placed in the group uand on type levers with faces 15u at level u, the other 24 characterswould be placed in group 2 and on type levers with faces at a level 151.As soon as a new line to be printed is read into a print storage buffer(not shown), a low power actuator 34 at each column would position itsinterposer 32 according to which group the character to be printed inthat column falls. Then printing would take place as usual.

Other equivalent configurations of the invention would includeeliminating the interposer 32 and shifting the print hammer 24 (nowspanning a single level) to two different levels to obtain the sameeffect. In another embodiment, separate type hammers 24 could beprovided for each level and the push rods could be moved to select theparticular type hammers. While the width of the faces 15:: and 151 onthe type levers 110, as shown, is twice the character spacing, makingthe width smaller would allow the type lever mass to be reduced withouteffecting the function of the invention, which provides an effectivedouble spacing of the type levers even though they are actuallypositioned side by side.

Whilethe invention has been particularly shown and described withreference to a preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and detail may bemade therein without departing from the spirit and scope of theinvention.

What is claimed is:

1. In a front printer,

a plu'ralityof character-bearing type members movable along a straightline path adjacent a print line on a document, said type members beingalso movable in a direction toward said document, and said type membershaving one striking surface on each type member with the strikingsurfaces of adacent type members being spaced different amounts in adirection perpendicular of the print line,

a plurality of print hammers positioned along the print line operable toactuate selected ones of said type members to move them toward saiddocument to perform a printing operation on said document, and

means including an interposer associated with each print hammerpositioned between said print hammers and said type members, saidinterposers being selectively movable perpendicular of said print lineto align with the striking surface of different ones of said typemembers, thereby providing selective impact between said type membersand said type hammers.

2. The invention as defined in claim 1 characterized by said typemembers comprising pivotally mounted levers positioned in 'side-by-siderelationand said type member striking surface portions extending beyondsaid levers in a direction along the print line, but at differentdistances perpendicular of said print line, so as to be in overlappingand yet non-interfering relation.

1. In a front printer, a plurality of character-bearing type membersmovable along a straight line path adjacent a print line on a document,said type members being also movable in a direction toward saiddocument, and said type members having one striking surface on each typemember with the striking surfaces of adjacent type members being spaceddifferent amounts in a direction perpendicular of the print line, aplurality of print hammers positioned along the print line operable toactuate selected ones of said type members to move them toward saiddocument to perform a printing operation on said document, and meansincluding an interposer associated with each print hammer positionedbetween said print hammers and said type members, said interposers beingselectively movable perpendicular of said print line to align with thestriking surface of different ones of said type members, therebyproviding selective impact between said type members and said typehammers.
 1. In a front printer, a plurality of character-bearing typemembers movable along a straight line path adjacent a print line on adocument, said type members being also movable in a direction towardsaid document, and said type members having one striking surface on eachtype member with the striking surfaces of adjacent type members beingspaced different amounts in a direction perpendicular of the print line,a plurality of print hammers positioned along the print line operable toactuate selected ones of said type members to move them toward saiddocument to perform a printing operation on said document, and meansincluding an interposer associated with each print hammer positionedbetween said print hammers and said type members, said interposers beingselectively movable perpendicular of said print line to align with thestriking surface of different ones of said type members, therebyproviding selective impact between said type members and said typehammers.